Industrial Strength
If you’re a fan of the industrial then there may be no better use for pipes, Edison bulbs, and other old machine parts than to hold your books together.
Tales from Mother Nature
You might be surprised to discover just how many things there are right outside your door that you may be able to use as bookends. A simple tree trunk, split it in half, and put some books between them for a simple, rustic look is one of them.
Geometric Concrete
For a very modern look, you can use pieces that add some shapely flair to your book collection. eHow has a great DIY tutorial on how to make your own geometric boulder bookend out of quick-drying concrete.